Wind towers are effective in harnessing energy without consumption of fossil fuels. Generally the taller the wind tower the more efficient it is. Typically wind towers are 60-80 meters in height.
It is desirable for efficiency to have taller wind towers. However as a wind tower gets taller, it is necessary that the base be of larger diameter. The diameter of a wind tower base is limited when the wind tower is manufactured off site by freeway underpass clearances. At larger diameter bases, it is not practical to transport the base portion of a wind tower by truck through a highway system.
Another limit on the height of wind towers is the size of a crane necessary to erect the wind tower on site.
Technology is being developed so that a wind tower of increased height can be constructed on site so that the transportation limit on wind tower size can be avoided. For example see Keystone U.S. Patent Publication Nos. 2011/0179623 and 2013/0074564. However, there remains the challenge of erecting a tall wind tower, particularly when the height is 100 meters or higher. Moreover, with very tall wind towers it is difficult to repair or replace the turbine, or major components such as bearings, rotors, and blades and upper portion of the wind tower. It is expensive to bring in a crane to access the top of a tall wind tower, even if such a crane is available. Although minor repairs can be made by a worker climbing the wind tower, if it is necessary to completely replace the turbine or blades or upper portion of the tower, that is not practical for very high wind towers, and the investment in the wind tower can be lost. Current technologies to build or assemble higher towers on site and in position exists (cast in place concrete, precast concrete components, slip forming); however, these methods are too slow and expensive to achieve the desired economic viability to make wind energy economical.
Accordingly, there is a need for a system for erecting and repairing tall wind towers on site.